Abstract:In order to understand the impact of climate warming on species diversity of understory vegetation, the effects of short-term 4-year warming (4℃) on understory vegetation diversity in subtropical evergreen broad-leaved natural forest were studied by means of soil warming. The results showed that short-term warming had no significant effect on the species composition of understory vegetation (P>0.05). There were 77 common species in understory vegetation, belonging to 38 families and 59 genera, including 65 species 53 genera and 37 families in warming plot and 63 species 52 genera and 36 families in control plot. Short-term warming increased the coverage of trees by 22.61%, and decreased the coverage of herbs and shrubs by 4.97% and 21.75%, respectively, and warming reduced the height of herbs, shrubs and trees by 21.64%, 3.37% and 5.59%, respectively. The ranking of importance value of ferns in herbaceous plants decreased after warming, and the importance value of trees increased (P>0.05). Although there was no significant difference in species diversity indexes after warming (P>0.05), they all decreased with warming. Therefore, the species composition of understory vegetation was not sensitive to short-term warming, which decreased the importance value of ferns in herbaceous plants and negatively affected the species diversity indexes. However, this response was not sensitive, and it was predicted that long-term warming might lead to the succession of the whole community from herbaceous to shrub and tree.

Abstract:Based on the general survey of Juglans regia in Xinjiang Wild Walnut Nature Reserve, the diameter level structure was used instead of age structure, the static life table of population was compiled by smoothing technique, and the population dynamics was predicted by time series model, so as to obtain the age level structure and dynamics of J. regia. The results showed that the middle age class was dominant in different slope directions, and the age structure was spindle-shaped with two small ends and big middle. Although the dynamic index V_pi of age structure of the four slope populations was greater than 0, the maximum was only 19.10%, and V_piʹ was extremely low, the maximum is 1.12%, the growth trend of J. regia population on sunny slope was the highest and the anti-interference ability and the population stability was the strongest, whereas the semi-sunny slope showed the lowest growth trend, the worst anti-interference ability and stability. There were multiple death peaks in all slope populations. The highest peak was at 15 age class on sunny slope, 15 and 18 age class on semi-sunny slope, and 9 age class on shady slope and semi-shady slope. The survival curves were closer to Deevey-II type. The number of individuals at middle age would decline after 2, 5 and 10 age classes in the future, while the number of old individuals would increase. Therefore, it was very critical for the protection of cespitose J. regia of young individuals.

Abstract:In order to understand the diversity of leaf phenotypic traits in Barthea barthei germplasm resources, the variance analysis, correlation analysis, principal component analysis and cluster analysis were conducted based on leaf traits of 139 individuals from 6 populations. The results showed that there were significant differences in leaf phenotypic traits among population groups and individuals. The variation coefficients of leaf traits ranged from 0.14 to 0.84 with average of 0.32, suggesting that the leaf traits of B. barthei varied greatly. Leaf traits could be extracted into five principal components, with a cumulative contribution rate of 88%, in which leaf area, leaf perimeter, leaf width, leaf length/width and leaf shape parameters were the main factors caused phenotype difference. Cluster analysis showed that 139 individuals of B. barthei resources could be divided into 6 groups, there were 34 individuals in group Ⅰ, 7 in group Ⅱ, 1 in group Ⅲ, 15 in group Ⅳ, 37 in group Ⅴ, and 45 in group Ⅵ, which showed that the individuals from different population were scattered in different groups, indicating that there were no significant relationship between leaf phenotype and source. Therefore, the leaf phenotypic diversity was abundant among different populations and individuals, which could provide basis for genetic improvement and new variety breeding.

Abstract:In order to explore the influencing factors of leaf senescence phenology in subtropical evergreen broad-leaved forest, the phylogenetic relationships, functional traits of 72 woody plants and climate factors were studied in Gutianshan subtropical evergreen broad-leaved forest in Zhejiang Province from November 2018 to February 2021. The results showed that the leaf coloration period was from September to December, and the leaf drop period was from October to December. There was no significant correlation between the number of leaf drop species and monthly average temperature, monthly average precipitation and monthly average sunshine duration. The monthly number of leaf coloration species had weak correlation with monthly average temperature and monthly average sunshine duration. The deciduous property had a significant effect on leaf coloration and leaf drop stages. The phylogenetic relationship among species had no significant effect on leaf coloration and leaf drop stages. Therefore, both biotic and abiotic factors could affect leaf senescence for evergreen broad-leaved species, which had an important value for improving the prediction models of autumn phenology.

Abstract:In order to explore the adaptation strategies of suitable woody plants to the extreme environment of tropical coral islands, Nerium indicum, Melaleuca bracteata, Morus alba, and Heritiera littoralis were transplanted to tropical coral island from the nursery of Wenchang City, Hainan Province, the morphological and anatomical characteristics of leaves and physiological characteristics of resistance of plants in two places were compared. The result showed that compared with Wenchang, the specific leaf area (SLA) of Morus alba in tropical coral island increased significantly. There was no significant difference in ratio of palisade tissue to sponge tissue (P/S) of N. indicum, while P/S of other three plants decreased significantly. The chlorophyll content of N. indicum and Morus alba increased significantly, while that of Melaleuca bracteata and H. littoralis decreased significantly. The total antioxidant capacity (T-AOC) of N. indicum, Melaleuca bracteata and H. littoralis increased significantly, while that of M. alba decreased significantly. The free proline (Pro) content in N. indicum leaves decreased significantly, while that of Melaleuca bracteata, Morus alba and H. littoralis increased significantly. Therefore, in order to adapt to the tropical coral island habitat, Morus alba and N. indicum showed a strategy of "enhancing carbon assimilation potential and sustaining higher damage", while Melaleuca bracteata and H. littoralis showed a strategy of "improving resistance and reducing carbon assimilation potential".

Abstract:The aim was to establish an evaluation system to screen tulip varieties with good growth adaptability and high ornamental value, which are suitable for landscape application. Twenty-nine imported varieties of Tulipa gesneriana were introduced and planted in Shanghai, the phenological period, 12 growth characteristics (plant height, plant width, etc.), and 32 ornamental characteristics (flower uniformity, flower type, flower color, etc.) were observed and measured. From all observed characteristics, 27 evaluation indexes (flowering uniformity, flower color, flower color uniformity, etc.) were further chosen to establish a comprehensive evaluation system based on AHP (analytical hierarchy process) and GRA (grey relation analysis). The results showed that 29 varieties could be divided into 4 grades according the comprehensive evaluation, grade I included 10 varieties, grade II had 12 varieties, grade III and IV only 4 and 3 varieties, respectively. The varieties in grade I and II generally possessed high ornamental value and strong adaptability, which were suitable for popularization and application in landscaping in Shanghai and surrounding areas in the future. These had an important guide in screening suitable tulip varieties for gardens in Shanghai and surrounding areas. The established evaluation system also has a positive reference significance for evaluating the application of other tulip varieties in landscape.

Abstract:In order to develop and utilize germplasm resources of zingiberaceae flowers, 84 species of germplasm resources of zingiberaceae flowers were collected and introduced, analyzed and evaluated in combination with growth, ornamental characteristics and economic use, and germplasm innovation was carried out by artificial cross breeding. The results showed that 77 of 84 introduction germplasm resources of Zingiberaceae survived with survival of 91.7%, flowering rate of 98.7%, and fruiting rate of 63.6%. Among all species, 59.5% had excellent growth, 7.1% had good growth, 25% had moderate growth and 8.3% had died. Most species of Zingiberaceae originally distributed in tropical and subtropical areas at middle and low altitudes could be preserved in Guangdong-Hong Kong-Macao Greater Bay Area, while those in tropics at middle and high altitudes and special habitats areas were not suitable. Stage domestication method could be used for introduction and preservation, and there were 60.7% species of multipurpose flowers. The hybrid breeding could not only innovate new germplasm, but also transfer and preserve superior genes of Zingiberaceae flowers.

Abstract:In order to understand the characteristics of phytoplankton community structure in Xisha Xuande Islands, the phytoplankton community composition and environmental factors sampled in February and November 2019 were analyzed. The results showed that 109 species of phytoplankton were found during the two voyages, among which Bacillariophyta were the most with 81 species. The dominant species varied between winter and autumn, Trichodesmium thiebautii, T. erythraeum, Asterionella notata, etc. were the dominant in winter, and did Thalassionema nitzschioides, Leptous danicus and Chaetoceros lorenzianus were in autumn. The average abundance of phytoplankton in winter[(5.27±6.14)×10⁷ cells/L] was significantly higher than that in autumn[(1.56±1.40)×10⁵ cells/L]. The structure of phytoplankton community was mainly affected by nitrite, salinity and other environmental factors. The average of Shannon-Wiener diversity index (H'), Pielou evenness index (J') and Margalef richness index (d') in winter and autumn were 3.15, 0.71, 1.36 and 3.28, 0.75, 1.77, respectively. As a whole, these indicated that phytoplankton community in Xuande Islands had high diversity and rich species, as well as complex and stable community structure in winter and autumn.

Abstract:To investigate the protective effect of Sargassum horneri polysaccharides (SHP) on H₂O₂-induced oxidative stress injury of human keratinocytes (HaCaT), the total antioxidant capacity (T-AOC), DPPH free radical, hydroxyl free radical (·OH) and superoxide anion free radical (O₂^·) were determined, and the antioxidant capacity of SHP in vitro and established the oxidative damage model of HaCaT cells induced by H₂O₂was evaluated. The protective effect of SHP on oxidative damage of HaCaT cells was evaluated by measuring cell survival rate, reactive oxygen species and enzyme activity. The results showed that the clearance rate of DPPH was 68% and the scavenging capacity of ·OH was 65.48 U/mL treated with 1 mg/mL SHP. The clearance capacity of O₂^· was 84.86 U/mL and T-AOC was 33.55 treated with 3 mg/mL SHP. SHP could significantly improve the viability of HaCaT cells by H₂O₂-induced oxidative damage. After, The survival rate of HaCaT cells increased from 56.85% to 80.57%, as well as the intracellular SOD activity treated with 100 μg/mL SHP, while the contents of ROS and MDA significantly reduced (P<0.05). Therefore, SHP had a protective effect on H₂O₂-induced oxidative stress injury of HaCaT cells, suggesting that SHP, a natural antioxidant, could be widely applied to cosmetics and cosmeceuticals.

Abstract:Viburnum japonicum is a species with extremely small populations, only distributing on islands. In order to evaluate the effect of salt spray stress on growth of V. japonicum, 4-year-old seedlings were treated with different salt spray concentrations (mass concentrations of NaCl in salt spray were 0%, 1%, 2% and 3%, respectively), the changes in photosynthetic rate, maximum photochemical efficiency (F_v/F_m), chlorophyll content (Chl) were measured. The results showed that V. japonicum treated with 1% salt spray could survive, but all plants died treated with more than 2% salt spray. With the increment of salt spray concentration, the maximum photosynthetic rate, F_v/F_m and Chl content in leaves generally decreased, and the light saturation point and light compensation point showed an upward trend. Therefore, it was indicated that salt spray stress affected plant photosynthesis by harming photosystem II reaction center, changing the range of available light energy and reducing chlorophyll content.

Abstract:In order to explore the YABBY transcription factor of Jatropha curcas, seven YABBY genes from five subfamilies were identified at the genome-wide level based on the newly published genome sequence of J. curcas. Members of the same subfamily had similar amino acid sequence, gene structure and conserved motifs. Two pairs of paralogs from YAB2 (JcYAB2A/JcYAB2B) and FIL/YAB3 (JcYAB1/JcYAB3) subfamily showed good collinearity, indicating that segmental duplication/whole genome duplication was the primary cause of YABBY gene family expansion. Purifying selection might be the main impetus during evolution, while candidates of YAB2 subgroup underwent more significant functional divergence. The expression patterns together with protein-protein interaction prediction suggested that JcYAB2B and JcYAB3 might play crucial roles in seed development, meanwhile the transcription of most JcYABs were remarkably repressed under exogenous cytokinin, drought or salinity stress. In addition, RNA sequencing and qRT-PCR analysis confirmed that the paralogous gene pair JcYAB2A/JcYAB2B exhibited differential cold-responsive transcription in leaves, and their newly identified transcripts were both dynamically accumulated during cold treatment. Therefore, it was speculated that JcYABs might participate in the regulation of low temperature response through functional competition or functional complementarity of spliceosome. These would help to understand the evolution of YABBY family, and elucidate how AS events play a crucial regulatory role in cold response of J. curcas.

Abstract:Based on literature review, field work and examination of specimens, the genus Ceropegia Linn. (Apocynaceae) in South China is revised, Ceropegia angustilimba Merr. is reinstated from the synonym of C. trichantha Hemsl., and detailed descriptions for the two species are provided; it is confirmed that the record of C. salicifolia H. Huber in South China is a misidentification of C. dolichophylla Schltr., and a detailed description of the latter species is provided.

Abstract:Bulbophyllum dresslerianum Z. D. Han & H. Wang (Orchidaceae), a new species from southern Yunnan, China, is described and illustrated. The new species belongs to section Tripudianthes Seidenf., sharing some vegetative and floral traits with B. dickasonii, B. kanburiense, B. rugosisepalum and B. tripudians, but differs on the basis of a suite of floral characters. Globular papillae decorate the lip epichile with the abaxial side and margins bearing sparse short glandular hairs. In addition, its lateral sepals are brownish-yellow and glabrous. A key to B. dresslerianum and its related species is provided. Currently, this species is only found in one population, its conservation status requires further assessment.

Abstract:Appendicula ovalis (Schltr.) J.J.Sm. ex Mansf, found in Hainan Tropical Rainforest National Park, was reported as a newly recorded species of Orchidaceae in China. It is originally distributed in Peninsular Malaysia, Sumatra, Java, Borneo and Sulawesi. It is different from four species of Appendicula recorded in China by morphology of branches in middle of stem, broad ovate leaf blades, single inflorescence bears only one flower and twisted lips with pink-purple markings. The detailed morphological and habitat description, and high- definition anatomy photograph of the newly recorded species are provided. Voucher specimen was deposited in the herbarium of College of Forestry, Hainan University (HUFB).

Abstract:In order to understand the nyctinasty of leaves and flowers of Oxalis corniculata, the leaf pillows and receptacles were studied by semi-thin section. The results showed that the leaves were completely closed after dark treatment, and three leaves were tightly closed downward with the leaf axis as the axis. The petals were completely closed and spiraled into bundles under dark for 8 hours, and the calyx clung to the spiral petals but did not spiral. The cortical parenchyma cells on the flexor side contracted and the parenchyma cells on the extensor side expanded when the leaf was opened. When the leaf was closed, cortical cells on the flexor side expanded, epidermal cells on the extensor side and parenchyma cells on the 3-5 layers of outer cortex contracted. When the flower closed, the five vascular bundles at the base of the container contracted and merged into two distinct vascular bundles, and the cell walls were thickened. Cells swell at corner of receptacle. Therefore, the contraction and expansion of flexor and extensor muscle cells in the leaf occipital control the nocturnal motion of the leaves of O. corniculata. The nocturnal motion of flowers is mainly related to the enlargement and contraction of the vascular bundles at the base of the receptorum and the cells at the corner of the receptorum.

Abstract:To clarify the chemical constituents in Casuarina equisetifolia, fourteen compounds were isolated by organic solvent extraction, fractionation, and a variety of chromatographic separation techniques. Based on spectroscopic data, their structures were identified as 5-hydroxy-3-methoxyphenyl-6-O-syringoyl-β-d-glucopy-ranoside (1), alpinoside A (2), heterophylloside C (3), 6''-O-vanilloylisotachioside (4), 3,4,5-trimethoxyphenyl-6-O-syringoyl-β-d-glucopyranoside (5), vanillin (6), syringaldehyde (7), 3,4-dihydroxybenzaldehyde (8), oleanolic acid (9), betulinic acid (10), β-sitosterol glucoside (11), daucosterol-6'-linoleate (12), (±)-lyoniresinol 2-O-a-rham-noside (13), and (-)-9-acetyl-isolariciresinol 9'-O-a-l-rhamnopyranoside (14). Among them, compound 14 is a new lignan derivative.

Abstract:Beta-glucan is a noncellulosic polysaccharide linked by β-(1,3) and β-(1,4) glycosidic bonds, mainly distributed in the endosperm and aleurone layer of cereal crop grains with the synthesis in the Golgi apparatus, transportation to the plasma membrane by vesicles, and deposition in the cell wall. Beta-glucan is effective in reducing cholesterol and blood sugar levels by increasing bile acid excretion and delaying glucose absorption. Members of the β-glucan synthase gene families were firstly identified in rice (Oryza sativa), and subsequently discovered in other cereal crops. There are three main subfamilies (CslF, CslH and CslJ) in β-glucan synthase with the formation via convergent evolution. These three subfamilies originated from different clades and evolved their respective functions independently. During evolution, the purifying selection pressure resulted in the high conservation of sequences for members of β-glucan synthase gene families. CslF subfamily members are relatively large and often form gene clusters on chromosomes, and CslF6 is the key gene mediating β-glucan synthesis. CslF subfamily members showed the relatively high expression levels in young tissues such as leaf bases, and they were affected by light intensity obviously. There are relatively few members in CslH and CslJ subfamilies, CslH genes presented the relatively high expression levels in mature tissues such as leaf tips, while CslJ genes showed the relatively high expression levels in young one like grains. The research progress on the phylogenetic relationships for members of β-glucan synthase gene families, the subcellular localization of β-glucan synthase, and the directional breeding in cereal crops were summarized. The accurate localization of β-glucan synthase genes on chromosomes is prospected for the future research. The review aims to promote the directionally breeding of cereal crops with high β-glucan content by the chromosome engineering.